Metering pump



Sept. 26, 1967 Filed April 15, 1965 F. D. BRILL ETAL METERING PUMP 4 Sheets-Sheet 1 INVENTORS.

FHA/VA 0. BR/LL R0) A. JOHNSON FREDERICK A. AC/(ERMA/V/V CARL B/AG/ Sept. 26, 1967 F. D. BRILL ETAL 3,343,728

METERING PUMP Filed April 13, 1965 4 Sheets-Sheet 2 l/VVE/VTORS FRANK 0. BRILL R0) A. JOHNSON FEEDER/0f A. AC/(ERMA/V/V By AHL 8/467 P 26, 1967 F. D. BRILL ETAL 3,343,728

METERING PUMP Filed April 13, 1965 4 Sheets-Sheet 5 INVENTORS. FRANK 0. BRILL l7 4 R0) A. JOHNSON FREDERICK A, AC/ ERMAN/V CARL B/A Byduf P 26, 1967 F. D. BRILL ETAL 3,343,728

METERING PUMP Filed April 13, 1965 4 Sheets-Sheet 4 INVENTORS FRANK 0. BRILL R0) .4. JOHNSON FREDERICK A. AC/(ERMA/V/V United States Patent f 3,343,728 METERING PUMP Frank Daniel Brill, Norridge, Roy A. Johnson, Chicago, Frederick A. Ackermann, Berwyn, and Carl Biagi, Berkeley, 1ll., assignors to The Seeburg Corporation, Chicago, 111., a corporation of Delaware Filed Apr. 13, 1965, Ser. No. 447,670 14 Claims. (Cl. 222309) This invention relates to pumping devices and more particularly to a metering pump adapted to rapidly provide a predetermined metered volume of a liquid such as water.

A pumping device capable of rapidly providing accurately measured volumes of water under pressure is a requisite to the successful operation of a vending machine which formulates and vends beverages by the cup. Specifically, a machine which freshly brews coflee having the flavor, aroma, and appearance of naturally brewed coffee in cup-size amounts in response to individual customer selection requires such a pumping device. The present invention provides a metering pump adapted to fulfill the operational requirements of such a coffee brewing machine. Of course, the pumping device of the present invention has utility in many other environments.

Briefly described, the present invention comprises means defining a pumping chamber having an inlet and an outlet and reciprocable piston means adapted, when actuated, to diminish the volume of the pumping chamber in order to force liquid through the chamber outlet. Sealing means, preferably in the form of a flexible diaphragm, are provided in order to effect a fluid tight seal between the piston means and pumping chamber. Rack means and pinion means drivingly engaged therewith are provided in association with the piston means for imparting reciprocal motion thereto, and cam controlled clutching means, responsive to the operation of drive means, are utilized in order to bring the pinion means into operative engagement with the drive means. Valve means are provided in association with the chamber inlet for controlling the flow of liquid therethrough, and cam means, responsive to the operation of the drive means, are provided for opening and closing the valve means.

A primary object of the present invention is to provide a device capable of pumping, under pressure, a liquid at a temperature approaching its boiling point, for example, water at one atmosphere of pressure at 210 F. to 211 F.

Another object of the present invention is to provide a pumping device capable of rapidly pumping accurately measured volumes of liquid under pressure.

A further object of the present invention is to provide a pumping device of the character described utilizing a power driven cam controlled rack and pinion driving arrangement for actuating a rolling diaphragm piston pump mechanism.

A still further object of the present invention is to provide a pumping device of the character described in which a cam controlled inlet valve is utilized to accurately control the metered amount of liquid pumped upon the actuation thereof, the said valve control cam being synchronously driven by the same power source utilized for the actuation of the rack and pinion drive arrangement.

These and other objects, advantages, and features of the subject invention will hereinafter appear, and, for purposes of illustration, but not of limitation, an exemplary embodiment of the present invention is shown in the accompanying drawings, in which:

FIGURE 1 is a side perspective view of a preferred embodiment of the present invention;

FIGURE 2 is a bottom perspective view thereof;

FIGURE 3 is a fragmentary bottom view showing the cam operated clutching arrangement;

35,343,723 Patented Sept. 26, 1967 FIGURE 4 is an upright sectional view taken substantially along line 4-4 in FIGURE 3; and

FIGURE 5 is an enlarged, fragmentary sectional view taken through the center of the mechanical inlet valve.

With reference to the drawings. FIGURES l and 2 generally illustrate a metering pump 10 having a pump frame 12 comprising a top 11 and a rear wall 13. A generally hollow member 14 comprising a top 14 and a side wall 14" is attached to the top 11 of pump frame 12 and defines therewith a chamber 15. The lower edge of side wall 14 has an outwardly turned flange 16 formed therealong and a sealing gasket 18, configured similarly to flange 16, is positioned between flange 16 and the top 11 of frame 12. A plurality of bolts 20 are threaded through flange 16, gasket 18, and the top 11 of pump frame 12 and into a plurality of bosses 22 provided beneath top 11. Thus, flange 16 is tightly sealed to top 11 so that the chamber 15 may function as a pumping chamber.

An outlet opening 24 is provided in member 14 and a conventional fitting 26, to which a delivery tube (not shown) may be attached, is suitably fixed therein. An inlet tube 28 passes through the member top 14 and an end portion 30 of tube 28 functions as an inlet valve seat in a manner that will hereinafter be described. As will be obvious to one skilled in the art, an outlet check valve (not shown) may be previded in the delivery tube adjacent fitting 26 in order to prevent liquid from flowing back from the delivery tube into the interior of chamber 15.

A pumping cylinder 34 (see FIGURES L4) is preferably formed integrally with frame 12. In the embodiment shown in the drawings, cylinder 34 is interconnected with the rear wall 13 of frame 12 by a pair of vertical walls 36.

As shown in FIGURE 4, the lower portion of cylinder 34 has an outer wall 35 and an inner Wall 38 so that an annular space 37 is formed therebetween. Walls 35, 38 are interconnected by a bottom Wall 46. A reciprocable piston assembly 40 is disposed within cylinder 34. The piston assembly 40 comprises a member having a generally flat top 42 and a downwardly extending side Wall 44 which is adapted to fit in the annular space between the walls 35, 38 of cylinder 34. The lowermost position of the piston assembly 40 is determined by the abutment of the bottom of side Wall 44 against bottom wall 46 of cylinder 34. A flexiblediaphragm 48 is stretched across the top 42 and is clamped thereto by means of a plate 50. Diaphragm 48 is stretched upwardly along the inside of cylinder 34 and is anchored to the top 11 thereof by suitable means (not shown).

The piston assembly 40 is attached to the upper end of a vertically reciprocable rack 52 by means of a bolt 54 which passes through a washer 56 and openings in plate 50, diaphragm 48, and top 42 and is anchored in a threaded hole in rack 52. Thus, all of the parts of piston assembly 40, including diaphragm 48, are tightly held to rack 52 and reciprocate vertically with rack 52 between a lowered position (shown in full lines in FIGURE 4) and a raised position (shown in broken lines in FIGURE 4). As the piston assembly 40 moves upwardly toward its raised position, diaphragm 48, together with plate 50, provides a pumping surface which effectively diminishes the volume of chamber 15 and results in liquid being forced out through inlet tube 28 and outlet opening 24 as described in detail hereinafter.

The provision of diaphragm 48 as a part of piston assembly 40 provides an important advantage of the present invention. A superior liquid-tight seal is obtained (as compared with conventional piston pumps) so that the danger of liquid lea'king downwardly into cylinder 34 beneath the assembly 40 is obviated. Additionally, longer .3 pump life and fewer maintenance worries are experienced, since there is no frictional contact between side 44 and the wall of cylinder 34.

A pair of grooves 56 are formed in the opposite sides of rack 52 (see FIGURES 2-4) and a guide member 58 has a cylindrical upper portion 60 which is adapted to be mounted inside the inner wall 38 of cylinder 34 as shown in FIGURE 4. A lower portion 61 of guide member 58 is generally semicircular (see FIGURES 2 and 3) and a pair of opposed runners 62 project inwardly from lower portion 61 and fit in the grooves 56 in rack 52. Member 58 functions as a guide for rack 52, grooves 56 sliding along stationary runners 62 as rack 52 reciprocates. In this manner, the vertical alignment of rack 52 (and hence of piston assembly 40) is maintained during the pumping operation.

Drive means are provided in order to impart reciprocal vertical motion to rack 52. An electric motor is mounted on a conventional gear box 72 in a manner such that a motor shaft 74 of motor 70 operatively engages the conventional inner parts (not shown) of gear box 72. Motor 70 is provided with power by means of a pair of wires W which lead to a conventional plug P. Plug P is mounted in a bracket B which is fixed to top 11. A drive shaft 76 is journaled in the gear box 72 and is adapted to be driven by the motor 70. The other end of shaft 76 is journaled through a collar 79 and in a bearing 78 (see FIGURE 4) in an end plate 80, which is mounted on frame 12 by conventional means such as bolts 82 (see FIGURE 1).

A pinion is mounted on shaft 76 for free rotation with respect thereto. The teeth of pinion 90 are adapted to mesh with a plurality of teeth 53 formed on the inner side of rack 52 (see FIGURE 1). In the position shown in FIGURES 3 and 4, pinion 90 is free floating on shaft 76 and is slidable laterally with respect thereto. However, even in the free floating position shown in the drawings, pinion 90 partially engages the teeth of rack 52 (see FIG- URE 3). A pair of projecting cars 94 are provided on one side of pinion 90 (see FIGURES 3 and 4) and a driving collar 96 is mounted on shaft 76 for rotation therewith by means of a pin 98. A pair of dogs 100 project in opposite directions from collar 96 and when pinion 90 is slid toward the right (as viewed in FIGURES 3 and 4) dogs 100 are adapted to fit between ears 94 on pinion 90. Thus, ears 94 and dogs 100 function as a clutch assembly so that, with pinion 90 disposed in a position wherein dogs 100 engage ears 94, shaft 76 may impart rotational movement to the pinion 90. Rotation of pinion 90 drives rack 52 and piston assembly 40 upwardly within cylinder 34. In this manner, a positive pumping stroke may be achieved.

Means are provided for controlling the engagement and disengagement of ears 94 from dogs 100, and hence controlling the driving interengagement of pinion 90 and shaft 76. A cylindrical extension 102 is provided in association with pinion 90. A groove 104 is formed in extension 102, which is preferably formed integrally with pinion 90. Extension 102 is both rotatable and slidable with pinion 90. A cam follower 106 (see FIGURE 4) has a downwardly extending bifurcated yoke 108 formed thereon. Yoke 108 has a pair of downwardly extending sides 110 on which are mounted respectively a pair of follower bearings 112. Bearings 1-12 ride in groove 104 in extension 102 as extension 102 and pinion 90 rotate. Also, lateral movement of yoke 108 is adapted to cause extension 102 and pinion 90 to slide along shaft 76.

Means are provided for controlling the lateral position of cam follower 106 and yoke 108 for the purpose of controlling the engagement of ears 94 on pinion 90 with dogs 100 on collar 96. A first cam 114 is mounted on shaft 76 for rotation therewith by means of a pin 115 which passes through cam 114 and shaft 76. The profile of cam 114 is recessed at 116 (see FIGURE 4). Cam follower 106 has a horizontal extension 118, and a ball 120, which is mounted on a vertical pin 122 for rotation in a horizontal plane, contacts the profile of cam 114. Ball is shown in engagement with the recessed portion 116 of the profile in FIGURE 4. As cam 114 is rotated by shaft 76, ball 120 gradually moves out of the profile recess 116 and is earned toward the right (as viewed in FIGURE 4). The movement of follower 106 causes extension 10 2 and pinion 90 also to move toward the right into a position wherein ears 94 and dogs 100 mate so as to bring the pinion 90 into driving engagement with shaft 76. When cam 114 has completed a full revolution, the cam follower 106 moves back toward the left (as shown in FIGURE 4), ball 120 again being disposed within the profile recess 116, and pinion 90 is disengaged from shaft 76.

Means are provided for biasing the cam follower 106 toward the position shown in FIGURE 4 (i.e., the position in which pinion 90 is disengaged from shaft 76). An arm 124 (see FIGURE 4) extends upwardly from follower 106 and is pivotally mounted to frame 12 by means of a pivot pin 1%. A hollow projection 128 is formed on arm 124 below pivot pin 126 and a coil spring '130 is positioned inside projection 128. A plunger 132 bears against spring and a shaft 133 of plunger 132 is attached to frame 12 (see FIGURE 4). Thus, spring 130 urges arm 124 to pivot in a clockwise direction (as viewed in FIGURE 4), resulting in follower 106 being urged toward its furthest leftward position (see FIGURE 4). However, as cam 11'4 rotates, follower 106 is cammed toward the right, and arm 1 24 pivots in a counterclockwise direction, against the bias of spring 130. As arm 124 pivots in a counterclockwise direction, follower 106 moves toward the right and also moves slightly downwardly, bearings :112 moving correspondingly slightly downwardly in groove 104. As follower 106 moves toward the right, extension 102 and pinion 90 move toward the right and ears 94 engage dogs 100 so as to provide for driving engagement between pinion 90 and shaft 76. When earn 114 has completed one full revolution, under the urging of spring 130, arm 124 pivots in a clockwise direction, ball 120 moves into profile recess \116, and pinion 90 is disengaged from shaft 76.

Means for controlling the flow of water through inlet tube 28 are also provided in association with drive shaft 76. As previously noted, the end 30 of tube 28 extends downwardly into the interior of chamber 15. As best shown in FIGURE 5, the lower edge of end 30 provides a seat against which a reciprocable valve assembly may be disposed in order to prevent water from entering chamber 15 through the tube 28. The valve assembly 140 comprises a semi-flexible washer 142 having a collar 144 extending therethrough. Washer 142 is mounted against a plate 146 and plate 146 is disposed over another plate 148 having downwardly extending side flanges 149.

A piston 150 is vertically reciprocable in a guide cylinder 152 which is mounted by suitable means in a boss 154 formed below the top 11 of frame 12. A flexible diaphragm 156 is stretched across the top of piston 150 and is seated in a recess in top 11. A bolt 158, passed through collar 144, plate 146, and diaphragm 156, is threaded into piston 150, thereby firmly fastening the entire valve assembly 140 together as a reciprocable unit. Means are provided for controlling the reciprocation of valve assembly 140 in order to regulate movement of washer 142 away from the inlet end 30 so as to permit liquid to flow through inlet tube 28. The periodic opening and closing of the valve assembly 140 is accomplished in the following manner. A spring retainer 160 is fixed to piston 150 by suitable means such as a clip ring 162, and a spring 164 is seated between retainer 160 and against a shoulder 165 formed in boss 154. Spring 164 thus biases bar 150 toward a lowered position wherein washer 142 is disposed away from inlet end 30.

A cam comprising a pair of adjustable plates 172, 174 is mounted on shaft 76 for rotation therewith. A

roller follower 176, mounted for rotation about a shaft 179 which passes through the sides of a yoke 178, is adapted to ride against the profile of cam 170. Both plates 172 and 174 form a part of the surface of cam 179 and the disposition of plates 172 and 174 with respect to each other is adjustable whereby the over-all configuration of the profile of cam 170 may be varied for a purpose that will hereinafter appear. Yoke 178 is fixed to a shaft 180 which passes through a guide collar 182 and a top portion 184 of a mounting bracket 186 to which the guide collar 182 is mounted. Bracket 186 is fixed to one of the wall members 36 (see FIGURE 1).

The upper end of shaft 180 is adapted to be received in a spring-loaded free floating manner in a socket 183 formed in piston 150. The upper end of shaft 180 has a spring retainer 190 formed thereon and a coil spring 192 is disposed in socket 188 between retainer 190 and another retainer 194 is disposed at the upper end of socket 188. Thus, the valve assembly 140 is held under tension against inlet end 30 when cam 170 is disposed in the position shown in FIGURE 5.

Valve assembly 141) is normally disposed in the opened position shown in FIGURE 4. As cam 170 rotates and roller follower 176 moves upwardly, the valve assembly 140 is closed in the following manner. Initially, spring 192 (which is stronger than spring 164) is compressed. Thereafter, spring 164 is compressed, moving piston 150 upwardly and seating washer 142 against inlet end 30. Valve assembly 140 is shown in its closed position in FIGURE 5. As cam 170 continues to rotate, the opposite sequence occurs and valve assembly 140 opens. Initially, spring 192 and spring 164 expand and piston 15!) moves downwardly, and, hence, washer 142 is unseated from inlet end 30.

With valve assembly 140 opened (as shown in FIG- URE 4), upward movement of piston assembly 40' forces liquid back out through inlet tube 28, as well as through outlet opening 24. Liquid is free to flow back out tube 28, since tube 28 leads from chamber 15 to an unpressurized reservoir (not shown), from which liquid normally flows into chamber 15 under the influence of gravity. In fact, if valve assembly 140 were maintained in its opened position throughout the entire pumping stroke of piston assembly 40, liquid would almost entirely flow through inlet tube 28 (rather than outlet opening 24) since outlet 24 is typically connected to a system that offers resistance to fluid flow.

Cam 170 rotates with shaft 76 and is adapted to close and thereafter open valve assembly 140 at predetermined points 'during the stroke of piston assembly 40. Liquid is pumped under pressure through outlet 24 during the period that valve 140 is closed. Thus, the times at which valve assembly 140 closes and opens during the pumping stroke of piston assembly 40 determines the metered volume of liquid pumped through outlet 24.

An especial advantage of the present invention is that the configuration of cam 170 may be adjusted by altering the relative disposition of plates 172 and 174. In this manner, the time during which valve assembly 140 is closed during the stroke of piston assembly 40 may be varied so as to adjust the metered volume of liquid pumpable from the chamber 15.

The operation of the metering pump may be described as'follows. With the pump 10 disposed in the position shown in the drawings (i.e., in the rest position) and with chamber filled with liquid, the motor 70 is energized via a pulse from the vending machine in which the pump is incorporated, and motor 70, via gear box 'ing the piston assembly 40 upwardly toward its FIGURE 4 broken line disposition. At the same time, cam 170 is adapted to cause the normally opened valve assembly 140 to close. After a predetermined time (regulated by the configuration of cam 170) valve assembly 140 reopens. On the upstroke of piston assembly 40, liquid is forced from chamber 15. However, so long as valve assembly 140 is opened, liquid is forced back out the inlet tube 28. It is substantially only while valve assembly 140 is held closed by cam 170 during the upstroke of piston assembly 46 that liquid is forced out of chamber 15 through outlet opening 24 and the delivery tube (not shown). Thus, the upward stroke of piston assembly-40, coupled with the length of time that valve assembly 140 is closed during the upward stroke, determines the metered volume of liquid forced through outlet opening 24.

The pumping stroke is completed when the piston reaches its FIGURE 4 broken line position. At this point, cam 114 is configured so that follower 106, under the urging of spring biased arm 124, moves back toward the left (as viewed in FIGURE 4) causing ears 94 to be disengaged from dogs 100. After the disengagement thereof, pinion is freely rotatable about shaft 76 (which continues to rotate) and, therefore, piston 40 falls downwardly to its FIGURE 4 full line disposition under the influence of gravity. As this occurs, chamber 15 is refilled with liquid which flows through inlet tube 28 under the influence of gravity, valve assembly having returned to its normal opened position during the continued rotation of cam 17 0.

A projecting pin 192' is provided on plate 172 and a conventional carry-over switch 194 is mounted on end plate 80. A pair of wires W lead from switch 194' to plug P. An actuating arm (not shown) of switch 194' is disposed in the path defined by the rotation of pin 192' about shaft 76. Pin 192' is positioned so as to trip the actuating arm of switch 194 when it has completed one full revolution in order to de-energize motor 70 and index the various parts of pump 10 in their respective rest positions.

It will be obvious to one skilled in the art that if it is desired to pump heated water through the metering pump 10, heating elements (not shown) may be provided within chamber 15 for the purpose of maintaining the liquid at an appropriate temperature. However, it is especially preferred that external heating elements (not shown) be utilized in order to maintain the liquid disposed in the interior of the chamber at the desired temperature.- The pumping device hereinbefore described is especially adapted to pump, under pressure, metered amounts of liquid at a temperature approaching its boiling point without experiencing cavitation and the resulting diminution in the volume of liquid pumped. For example, the device of the present invention is capable of pumping metered volumes of water at a pressure of one atmosphere and at a temperature of 210 F. or 211 F. As such, the device of the present invention provides a marked advance over convention-a1 piston pumping devices.

The utilization of the cam operated clutching arrangement for the rack and pinion driving mechanism utilized herein provides a simple, yet reliable, actuating means and contributes significantly to the rapidity with which the accurately measured volume of liquid is pumped from the chamber upon initiation of the operational cycle. The fact that liquid is disposed in the pumping chamber with the pumping device indexed in its rest position also contributes to the quickness of the devices response.

In addition, the provision of the rolling diaphragm seal within the pumping chamber provides an advance over conventionally utilized piston pumping arrangements, in that superior sealing is provided and fewer maintenance problems are experienced. Furthermore, utilization of the cam-controlled mechanical inlet valve, which is responsive to the motive power utilized in the operation of the pump driving mechanism, provides a simple, yet accurate, means for adjustably controlling the volume of liquid pumped during each operation of the pumping device.

It should be understood that various changes and modifications may be made in the details of construction, arrangements, and operations of the various elements without departing from the spirit and the scope of the present invention, as defined in the appended claims.

What is claimed is:

1. A device for pumping predetermined metered volumes of liquid comprising:

a frame;

means in combination with the frame and defining therewith a umping chamber having an inlet and an outlet provided in an upper end thereof;

a piston mounted in the frame for reciprocal movement between .a first position and a second position, movement thereof from the first to the second position being adapted to diminish the effective volume of the pumping chamber;

a flexible diaphragm adapted to interconnect the piston and the .pumping chamber so as to effect a seal therebetween;

a rack slidably mounted in the frame for reciprocal movement with respect thereto, the said rack being operatively connected to the piston whereby reciprocal movement of the rack causes the piston to move between its first and second position;

a drive shaft journaled in the frame for rotation with respect thereto;

a pinion mounted on the drive shaft for rotational and axial movement with respect thereto, the said pinion drivingly engaging the rack;

driving pin means mounted on the drive shaft for rotation therewith;

pin engaging means on the pinion, engagement of said pin engaging means with said driving pin means being adapted to effect driving engagement between the pinion and the drive shaft;

means biasing the pinion toward a position wherein it is disengaged from the drive shaft;

cam means mounted on the shaft for rotation therewith, the said cam means being adapted to cause the pin engaging means on the pinion to engage the driving pin means on the shaft during a predetermined interval during a revolution of the drive shaft; and

means for rotating the drive shaft.

2. A device, as claimed in claim 1, and further comprising:

a normally opened valve in association with the chamber inlet for controlling the flow of liquid through the inlet; and

second cam means mounted on the drive shaft for rotation therewith, the said second cam means being adapted to control the opening and closing of the valve,

whereby the volume of liquid pumpable from the pumping chamber is metered.

3. A device, as claimed in claim 1, and further comprising:

a normally opened mechanical valve in association with the chamber inlet for controlling the fiow of liquid through the inlet; and

adjustable cam means mounted on the drive shaft means for rotation therewith, the said adjustable cam means being adapted to control the opening and closing of the valve, adjustment of the adjustable cam means being adapted to vary the volume of liquid which flows through the chamber inlet,

whereby the volume of liquid pumpable from the pumping chamber is metered and adjustable.

4. A device, as claimed in claim 3, wherein the means for rotating the drive shaft includes an electric motor, and further comprising:

switching means responsive to the rotation of the drive shaft, the said switching means being adapted to de-energize the electric motor after the drive shaft has undergone a cycle of revolution. 5. A device for pumping predetermined metered vo1- umes of liquid comprising:

means defining a pumping chamber having an inlet and an outlet, the liquid fed to the pumping chamber through the inlet being propelled solely by the force of gravity; reciprocably movable piston means for altering the effective volume of the pumping chamber to discharge the liquid therein; piston driving means for reciprocating the piston means; valve means in association with the chamber inlet for governing the fiow of liquid through the inlet; and cam means in association with the piston driving means for controlling the opening and closing of the valve means in such a manner that a predetermined volume of liquid in the pumping chamber is discharged through the inlet, whereby the volume of liquid pumpable from the pumping chamber through the outlet is metered. 6. A device, as claimed in claim 5, and further comprising:

means for adjusting the cam means so as to vary the volume of liquid which flows through the chamber inlet, whereby the volume of liquid pumpable from the pumping chamber is adjustable. 7. A device, as claimed in claim 5, and further comprising:

diaphragm means for effecting a seal between the piston means and the pumping chamber. 8. A device for pumping predetermined metered volumes of liquid comprising:

means defining a pumping chamber having an inlet and an outlet, the liquid fed to the pumping chamber through the inlet being propelled solely by the force of gravity; reciprocably movable piston means for altering the effective volume of the pumping chamber to discharge the liquid therein; piston moving means adapted to reciprocate the piston; drive means; clutch means in association with the piston moving means and the drive means adapted, when actuated, to effect driving engagement between the piston moving means and the drive means; first cam means responsive to the drive means for actuating the clutch means; valve means in association with the chamber inlet for governing the flow of liquid through the inlet; second cam means responsive to the drive means for controlling the opening and closing of the valve means in such a manner that a predetermined volume of liquid in the pumping chamber is discharged through the inlet; and means for adjusting the second cam means in order to vary the predetermined volume of liquid which flows through the chamber inlet, whereby the volume of liquid pumpable from the pumping chamber is metered and adjustable. 9. A device for pumping predetermined metered volumes of liquid comprising:

means defining a pumping chamber having an inlet and an outlet; reciprocably movable piston means for altering the effective volume of the pumping chamber; rack means for reciprocating the movable piston means; pinion means drivingly engaging the rack means; drive means; clutch means in association with the pinion means and the drive means adapted, when actuated, to effect driving engagement between the pinion means and the drive means;

first cam means responsive to the drive means for actuating the clutch means;

valve means in association with the chamber inlet for governing the flow of liquid through the inlet;

second cam means responsive to the drive means for controlling the opening and closing of the valve means; and

means for adjusting the second cam means in order to vary the volume of liquid which flows through the chamber inlet,

whereby the volume of liquid pumpable from the pumping chamber is metered and adjustable.

10. A device for pumping predetermined metered volumes of liquid comprising:

means defining a pumping chamber having an inlet and an outlet, the liquid fed to the pumping chamber through the inlet being propelled solely by the force of gravity;

reciprocally movable piston means for altering the effecting volume of the pumping chamber to discharge the liquid therein;

valve means in association with the chamber inlet for governing the flow of liquid through the inlet;

diaphragm means for effecting a seal between the piston means and the pumping chamber;

rack means for reciprocating the piston means;

pinion means drivingly engaging the rack means;

drive means;

clutch means in association with the pinion means and the drive means adapted, when actuated, to effect driving engagement between the pinion means and the drive means;

first cam means responsive to the drive means for actuating the clutch means; and

second cam means responsive to the drive means for controlling the opening and closing of the valve means so that a metered volume of liquid is discharged through the outlet and the remainder of the liquid in the pumping chamber is discharged through the inlet.

11. A device for pumping predetermined metered volumes of liquid comprising:

means defining a pumping chamber having an inlet and an outlet, the liquid fed to the pumping chamber through the inlet being propelled solely by the 4 10 her through the inlet being propelled solely by the force of gravity;

a position reciprocably movable between a first position and a second position, movement thereof from the first position to the second position being adapted to diminish the effective volume of the pumping chamber to discharge the liquid therein;

a normally opened valve in association with the chamber inlet for controlling the flow of liquid through the inlet;

a flexible diaphragm member adapted to effect a seal between the piston and the pumping chamber;

rack means for moving the piston between its first and its second positions;

drive shaft means;

means for rotating the drive shaft means;

pinion means on the shaft means and normally rotatable with respect thereto, the pinion means drivingly engaging the rack means;

clutch means in association with the pinion means and the shaft means adapted, when actuated, to effect driving engagement between the pinion means and the shaft means;

first cam means mounted on the drive shaft means for rotation therewith, the first cam means being adapted to control the actuation of the clutch means; and

second cam means mounted on the drive shaft means for rotation therewith, the second cam means being adapted to control the opening and closing of the valve so that a metered volume of liquid is discharged through the outlet and the remainder of the liquid in the pumping chamber is discharged through the inlet.

13. A device for pumping predetermined metered volumes of liquid comprising:

means defining a pumping chamber having an inlet and an outlet, the liquid fed to the pumping chamber through the inlet being propelled solely by the force of gravity;

a piston reciprocably movable between a first position and a second position, movement thereof from the first position to the second position being adapted to diminish the effective volume of the pumping chamber to discharge the liquid therein;

a normally opened valve in association with the chamber force of gravity; inlet for controlling the fiow of liquid through the reciprocally movable piston means for altering the efinlet;

fective volume of the pumping chamber to discharge a flexible diaphragm member adapted to effect a seal the liquid therein; between the piston and the pumping chamber; valve means in association with the chamber inlet rack means for moving the piston between its first and for governing the fiow of liquid through the inlet;

diaphragm means for effecting a seal between the piston means and the pumping chamber;

rack means for reciprocating the piston means;

pinion means drivingly engaging the rack means;

drive means;

clutch means in association with the pinion means and the drive means adapted, when actuated, to effect driving engagement between the pinion means and its second position;

drive shaft means;

means for rotating the drive shaft means;

pinion means on the shaft means and normally rotatable with respect thereto, the pinion means drivingly engaging the rack means;

clutch means in association with the pinion means and the shaft means adapted, when actuated, to effect driving engagement between the pinion means and the shaft means;

the drive means; d h cam means responsive to the drive means for actuating cam {means molinte on t e dnve Shaft. means for the clutch means. and tatron therewith, the cam means being adapted to control the actuation of the clutch means; and flgi igttriifiilgil igsgfgigg $0321; 332 1262 123: adjustable cam means mounted on the drive shaft means means so that a metered volume of h u d s d for rotation therewith, the ad ustable cam means h r d thr h th n t d th q being adapted to control the opening and closing of :ha i rd ile pinging 311mb; l t i h d tlrrle valve ls10 th'ilt a metered volume of liquid is dise 1q 1 in v 1 e g c arged t roug the outlet and the remainder of through the inlet, adjustment of the ad ustable cam the liquid in the pumping chamber is discharged means being adapted to vary the volume of llqllld through the inlet, adjustment of the adjustable cam which flows out of the chamber through the inlet. 12. A device for pumping predetermined metered means being adapted to vary the volume of liquid which flows out through the chamber inlet.

volumes of liquid comprising:

means defining a pumping chamber having an inlet and an outlet, the liquid fed to the pumping cham- 14. A device for pumping predetermined metered volumes of liquid comprising:

means defining a pumping chamber having an inlet and 1 1 1 2 an outlet, the liquid fed to the pumping chamber adapted to vary the fixed volume of liquid which through the inlet being propelled solely by the force flows out of the pumping chamber through the inlet. of gravity; piston means for altering the effective volume of the References Cited pumping chamber totdischaggletghe llilquiri3 thereir;;f 5 UNITED STATES PATENTS va ve means 1n associa ion Wl e c am er in e or governing the flow of liquid through the inlet; i P 2 5 i piston driving means for actuating the piston means; 3O23936 3/1962 3 g i 222 333 X and adjustable cam means responsive to the piston driving 10 5:55a 31 2232 means for controlling the opening and closing of the valve means so that a metered volume of liquid is q discharged through the outlet and the remainder of ROBERT REEVES lirlmm} Exammer the liquid in the pumping chamber is discharged HADD LANE, Exammefl through the inlet, adjustment of the cam means being 15 

5. A DEVICE FOR PUMPING PREDETERMINED METERED VOLUMES OF LIQUID COMPRISING: MEANS DEFINING A PUMPING CHAMBER HAVING AN INLET AND AN OUTLET, THE LIQUID FED TO THE PUMPING CHAMBER THROUGH THE INLET BEING PROPELLED SOLELY BY THE FORCE OF GRAVITY; RECIPROCABLY MOVABLE PISTON MEANS FOR ALTERING THE EFFECTIVE VOLUME OF THE PUMPING CHAMBER TO DISCHARGE THE LIQUID THEREIN; PISTON DRIVING MEANS FOR RECIPROCATING THE PISTON MEANS; VALVE MEANS IN ASSOCIATION WITH THE CHAMBER INLET FOR GOVERNING THE FLOW OF LIQUID THROUGH THE INLET; AND CAM MEANS IN ASSOCIATION WITH THE PISTON DRIVING MEANS FOR CONTROLLING THE OPENING AND CLOSING OF THE VALVE MEANS IN SUCH A MANNER THAT A PREDETERMINED VOLUME OF LIQUID IN THE PUMPING CHAMBER IS DISCHARGED THROUGH THE INLET, WHEREBY THE VOLUME OF LIQUID PUMPABLE FROM THE PUMPING CHAMBER THROUGH THE OUTLET IS METERED. 